#pragma once
#include "Channel.hpp"
#include <unordered_map>
#include <vector>

#define MAX_EPOLLEVENTS 1024
class Poller {
    private:
        int _epfd;
        struct epoll_event _evs[MAX_EPOLLEVENTS];
        std::unordered_map<int, Channel *> _channels;
    private:
        //对epoll的直接操作
        void Update(Channel *channel, int op) {
            // int epoll_ctl(int epfd, int op,  int fd,  struct epoll_event *ev);
            int fd = channel->Fd();
            struct epoll_event ev;
            ev.data.fd = fd;
            ev.events = channel->Events();
            int ret = epoll_ctl(_epfd, op, fd, &ev);
            if (ret < 0) {
                log_message(ERROR, "EPOLLCTL FAILED!");
                std::cerr << std::strerror(errno);
            }
            return;
        }
        //判断一个Channel是否已经添加了事件监控
        bool HasChannel(Channel *channel) {
            auto it = _channels.find(channel->Fd());
            if (it == _channels.end()) {
                return false;
            }
            return true;
        }
    public:
        Poller() {
            _epfd = epoll_create(MAX_EPOLLEVENTS);
            if (_epfd < 0) {
                log_message(ERROR, "EPOLL CREATE FAILED!!");
                abort();//退出程序
            }
        }
        //添加或修改监控事件
        void UpdateEvent(Channel *channel) {
            bool ret = HasChannel(channel);
            if (ret == false) {
                //不存在则添加
                _channels.insert(std::make_pair(channel->Fd(), channel));
                return Update(channel, EPOLL_CTL_ADD);
            }
            return Update(channel, EPOLL_CTL_MOD);
        }
        //移除监控
        void RemoveEvent(Channel *channel) {
            auto it = _channels.find(channel->Fd());
            if (it != _channels.end()) {
                _channels.erase(it);
            }
            Update(channel, EPOLL_CTL_DEL);
        }
        //开始监控，返回活跃连接
        void Poll(std::vector<Channel*> *active) {
            // int epoll_wait(int epfd, struct epoll_event *evs, int maxevents, int timeout)
            int nfds = epoll_wait(_epfd, _evs, MAX_EPOLLEVENTS, -1);
            if (nfds < 0) {
                if (errno == EINTR) {
                    return ;
                }
                log_message(ERROR, "EPOLL WAIT ERROR:%s\n", strerror(errno));
                abort();//退出程序
            }
            for (int i = 0; i < nfds; i++) {
                auto it = _channels.find(_evs[i].data.fd);
                assert(it != _channels.end());
                it->second->SetREvents(_evs[i].events);//设置实际就绪的事件
                active->push_back(it->second);
            }
            return;
        }
};
